In order to improve the dynamic contrast and layering of the display, dynamic backlight modulation technology is usually used to control backlight brightness of liquid crystal display devices. Dynamic backlight modulation technology mainly includes global backlight modulation and partitioned backlight modulation. The global backlight modulation usually controls a backlight driver by a brightness control signal directly so as to drive all backlight sources to emit brightness corresponding to the brightness control signal. In order to protect the reliability of the backlight sources, maximum backlight brightness is usually controlled below a rated operating brightness. Partition backlight modulation is to divide the backlight matrix into a plurality of backlight partitions virtually, and the backlight driver can drive each of the backlight partitions. The backlight processor extracts a backlight brightness value of each of the backlight partitions according to a grayscale value of an image block corresponding to the backlight partition, and calculates an average backlight brightness value of the plurality of backlight partitions to determine an adjustment value and then adjusts the backlight brightness values of the partitions to determine target backlight brightness values. The target backlight brightness values are sent to the backlight driver through a brightness control signal to drive the backlight driver to provide the backlight needed by the respective backlight partitions.